1. Field of the Invention
The present invention relates to an insertion device comprising an insertion section extending along a longitudinal axis, and a rotation unit rotatable relative to the insertion section in directions around the longitudinal axis.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 2008-220672 has disclosed an endoscope device which is an insertion device including an insertion section extending from a proximal direction toward a distal direction along a longitudinal axis. In this endoscope device, a motor which is a driving member is driven, and the insertion section thereby moves along the longitudinal axis. The driving direction and driving amount of the motor are detected by an encoder. An insertion length calculator then calculates a dimension along the longitudinal axis between the motor and the distal end of the insertion section in accordance with the detected driving direction and driving amount of the motor. As a result, a dimension of the part of the insertion section inserted into a lumen along the longitudinal axis is calculated. In this endoscope device, an image of a subject is generated by an image capture. The dimension of the part inserted into the lumen along the longitudinal axis and the image of the subject are stored in a memory in association with each other.
Jpn. Pat. Appln. KOKAI Publication No. 2005-323888 has disclosed an endoscope device which is an insertion device including an insertion section extending along a longitudinal axis, and a rotation unit rotatable relative to the insertion section in directions around the longitudinal axis. The rotation unit includes a spiral fin portion spirally extending about the longitudinal axis. A position in the spiral fin portion is toward a first around-axis direction which is one of directions around the longitudinal axis as the position in the spiral fin portion is from a proximal direction toward a distal direction. In a lumen, the rotation unit is rotated in the first around-axis direction while the spiral fin portion is in contact with a luminal wall, so that a first propulsive force is applied to the insertion section and the rotation unit toward the distal direction. On the other hand, the rotation unit is rotated in a second around-axis direction opposite to the first around-axis direction while the spiral fin portion is in contact with the luminal wall, so that a second propulsive force is applied to the insertion section and the rotation unit toward the proximal direction. The first propulsive force and the second propulsive force ensure the mobility of the insertion section in directions parallel to the longitudinal axis even in a lumen such as a small intestine having many bent parts.